Rotary piston combustion engine of trochoid type

ABSTRACT

A trochoid-type rotary piston combustion engine has a housing composed of at least one shell and at least two parallel end parts as well as an inlet and an outlet passage equipped with a throttle. Each shell is arranged between two end parts connected thereto by tension bolts to bound an interior space in which is rotatably arranged a multi-arcuate piston. The piston is provided with sealing members slidable along the inner faces of said housing. Lubrication of the housing inner face is in the form of a lubricating oil supply orifice opening into the intake chamber.

United States Patent 11 1 Steinwart Sept. 9, 1975 [54] ROTARY PISTON COMBUSTION ENGINE 3,838,950 l0/l974 Andriulis 418/97 X 0F TROCHOID TYPE FOREIGN PATENTS OR APPLICATIONS Inventor: Johannes Steinwart, Bad 1,196,914 7/1965 Germany [23/801 Friedrichshall, Germany 731 Assignees: Audi NSU Auto Union Primary Examinerc- Husar Akti n h ft; wankd GmbH Assistant Examiner-Michael Koczo, Jr. Germany Attorney, Agent, or Firm-Kane, Dalsimer, Kane, Sullivan and Kurucz [22} Flled: Mar. 18, 1974 V [21] Appl. No.: 451,770 [57] ABSTRACT A trochoid-type rotary piston combustion engine has a [30] Foreign Application Priority Data housing composed of at least one shell and at least two Mar- 22 1973 Germany N 2314251 parallel end parts as well as an inlet and an outlet pas sage equipped with a throttle. Each shell is arranged 52 11.5. CI 418/99; 418/100 between two end Parts nnected thereto by tension 51 Int. c1. F01C 21/04 bolts bOund interior Space in which [58] Field of Search l H 123/801, 196 R; 184/55 R; arranged a multi-arcuate piston. The piston is pro- 4I8/83 84, 87 97 99 [0O vided with sealing members slidable along the inner faces of said housing. Lubrication of the housing inner [56] References Cited face is in the form of a lubricating oil supply orifice UNITED STATES PATENTS opening into the intake chamber. 3.771903 11/1973 King et al. 418/84 7 Claims, 7 Drawing Figures PATENTED 91975 3,904,329

sum 3 or 3 Fig 6 Fig. 4

ROTARY PISTON COMBUSTION ENGINE OF TROCIIOID TYPE BACKGROUND OF THE Invention In known rotary piston combustion gengines with inner face lubrication, lubricating oil is supplied through orifices arranged in-""the shell or end parts and opening into the angles between shell and' end parts. The lubricating oil orifices are circumferentially ar ranged in a manner so that they are swept by the radial sealing strips of the piston eitherimme diately before or after the inlet passage. In this mode" of lubricant supply, however, some of the oil may be entrained by the fuel mixture, so that lubricating oil will burn unused to gether with the fuel mixture without having performed any lubricating function. This is the case especially when a high negative pressure prevails in the working chamber, sucking the oil, previously accumulated at low negative pressure, out of the orifices and swirling it into the working chamber. Furthermore, owing to the narrow lubricant orifice, uniform supply of lubricant on both sides of the ports may be jeopardized, since when the lubricant is cold a higher delivery pressure must be overcome, and deposits may clog the orifices. Any partial or total failure of lubricant supply may shorten the life of the inner faces of the housing and the sliding sealing members.

SUMMARY OF THE INVENTION The object of the invention is to provide uniformly proportioned supply of lubricant to the inner faces of the housing and the sealing members sliding over them while preventing combustion of any major quantity of lubricant that may be unused. 4

This object is effectively accomplished by'having the lubricant orifice opening into a passage communicating with the atmosphere at one end and opening into the intake chamber near the inlet passage at the other end. An air throttling means is coupled with the throttle and when the throttle is closed a small flow section is'obtained and as the throttle progressively opens. a progressively large flow section results. 1

The oil entering the air passage is permitted to wet the passage walls with a film of oil by adhesion by the passing air. The film is evenly propelled all the way into the intake chamber separately from the fuel mixture. The stream of air propelling the oil is more or less effective and more or less vigorously entraining of a corresponding quantity of oil depending on the setting of the throttle.

The passage communicating with the atmosphere may lead from the axial midpoint of the outer shell surface in a radial direction and open into enlarged tension bolt hole nearest the inlet passage. In each of the adjacent faces of the end parts a groove may be provided that extends from the bolt hole to apoint in the intake chamber. The use ofa bolt holehas the advantage that no additional holes in the shell will be required.

In a further refinement of the invention the cross section of the groove in the end part may have a profile guiding the flow obliquely and radially outwardly towards the shell bearing surface. In this manner, the preponderance of the oil film traveling in the interior space may be guided onto the sliding surfacesof the sealing strips and so distributed by the incoming air and/or the fuel mixture that the sealing strips sliding along the shell bearing surface receive adequate lubrication throughou'ttheir width.

According to another proposal, the groove may open into the intake chamber near the inlet control aperture in the region of=the greatest angle of sweep of the seal ing strips. By virtue of this arrangement of the lubricant delivery groove=and owing to the setting of the sealing strips of the piston at a given time, the lubricant forced into the working chamber may be propelled along the sealing strips all the way to the axial sealing flanges of the piston.

The air throttling means may consist of a rotary control valve for determining the volume of air flow. The valve is mounted on the shaft of the throttle and is tightly enclosed by a housing having one air inlet and one air outlet, the outlet being connected by piping to the enlarged bolt hole. The air inlet may expediently be in communication with the fresh air flowing from the air filter into the air intake of the carburetor.

To prevent emptying of the lubricant orifice and interruption of further lubricant supply when the negative pressures in the working chamber are high, it is further proposed that a spring-loaded check valve opening under oil pressure be arranged in the lubricant orifice.

Lubricant may for example be supplied by means of an intermediate-delivery oil proportioning pump with each shell receiving a separate proportion of comparable amount.

The passage communicating with the atmosphere gine is cold is reduced, and the orifices carrying lubrii cant are cleaned in this phase. In a combustion engine with suction pipe'injection having its own cold start assisting means, it is possible to arrange for some of the fuel jet to reach the air inlet beginning in the air intake pipe and arrive in the working chamber by way of the air throttling means and the passage. The lubrication of inner housing surfaces according l to the invention may be applied to rotary piston combustion engines with carburetor operation, but advantageously also to gasoline injection and gas operation.

An embodiment of the invention is represented byl way of example in the drawing and will be described; below.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I shows a partial view of a longitudinal section of a rotary piston combustion engine having two working chambers.

FIG. 2 is a partial view of a longitudinal section similar to FIG. 1 showing a second embodiment.

FIG. 3 shows a cross-section of part of the housing taken along line 1-1 in FIG. I.

FIG. 4 shows a section of a schematically represented air throttling means coupled with the throttle in accordance with one form of the invention.

FIG. 5 shows a view of the rotary control valve of the air throttling means of FIG. 4.

FIG. 6 shows a section of a schematically represented air throttling means coupled with the throttle in accordance with a second embodiment.

FIG. 7 shows a view of the rotary control valve of the air throttling means of FIG. 6.

DETAILED DESCRIPTION.

Referring first to FIG. 1. the housing of a rotary piston combustion engine having, for example. double working chambers consisting of one shell leach and end parts 2 as well as a substantiallyparallel interposed part 3. The tension bolts 4 assemble theparts which bound an interior space S in which is rotatably arranged a multi-arcuate piston 6 provided with sealing members 7 sliding along the faces 8 of end parts 2 and between part 3 as well as the shell bearing surface 9. The passage 10 communicating with the atmosphere opens into the enlarged bolt hole 12 nearest the inlet passage 11 which hole is in communication at the adjacent faces 8, with grooves 13 extending in end parts 2 and between part 3 from bolt hole l2 into the interior 5 near the inlet passage l l. The bolt holes 12 in the two shells l are separated from each other by sealing means 18 to prevent them from affecting each other.

A stream of air generated by the negative pressure in the working chamber propels the lubricant emerging from orifice l4 along the walls of passage [0, bolt hole 12 and groove 13 into the working chamber inside the interior spaces to lubricate the sealing members 7. The lubricant delivered, for example. by an intermittent delivery oil proportioning pump through piping 15 before it enters the lubricant orifice l4, passes a check valve 16 set to counteract a high negative pressure generated inside the working chamber and thus prevents exhaustion of the lubricant supply line and orifice.

It is possible alternatively in cold starting to connect the passage 10 communicating with the atmosphere to a source of fuel. for example, a cold start assisting means, so that in the starting phase a fuel-oil mixture passes directly into the working chamber and, at the same time. supplies the sealing members 7 with lubricant which is thusly flushed in.

FIG. 2 represents the second embodiment of a groove 13a arranged in end part 2 and between part 3. the conformation of which is such that the stream of air propelling an oil film is directed obliquely radially outward and thus principally reaches the shell bearing surface 9 so that the sealing members 7 arranged in piston 6 may thence be supplied with lubricant.

The arrangement represented in PK]. 3 exhibits the orifice located near an end inlet ll of a groove 13 or 130. Since the sealing members 7 arranged in piston 6 form their greatest angle of swing when sliding over groove 13 cr I30. the setting of sealing strip 70 may cause lubricant to be picked up from the mouth of groove 13 or 130 and delivered radially inward by way of sealing pin 7!; as far as the sealing flanges 7c.

The air throttling means shown in FIG. 4 consists of a rotary control valve 19 arranged on the shaft 20 of the throttle 20a of the illustrated carburetor and an in tegrated housing 2} closed with a cover 22 and having an air inlet 25 connected to an air intake pipe 24 of the carburetor and an air outlet 26 connected to passage [0 in H0. l. The rotary control valve 19 has one face in tight contact with a radial inner surface of housing 23 whence the air outlet 26 proceeds In idling. the air throughput is matched to the idling system of the car buretor. the rotary control valve 19 freeing only a small hole 27 shown in FlG. 5. so that little air can flow into air inlet 26 and thence to passage it) in FIG I. As the throttle opens. an enlarging aperture 18 rotates in front of the air outlet 21] and thus permits a larger stream of air towards passage 10in. FIG. I. In a combustion engine with suction pipe 'injeotion'. a cold start assisting means 29 may so arranged in the air intake pipe 24 of the carburetor so that ih cold starting, its fuel jet will reach awnings. 1

PK]. 6 shows an airithrottling means in a second embodiment having a housing 30 in which a rotary control valve-31 is arranged on a shaft 20 of a throttle. As the throttle opens, the val-ve exposes an aperture 32 enlarging in circumferential direction on its peripheral surface as shown in FIGJZ, opposite air outlet 26.

The air inlet 25 of air throttling means of H05. 4 and 6 is preferably connected by way of an air intake pipe 24 of the engine to an existing air filter (not shown).

What is claimed:

1. A rotary piston combustion engine of trochoid type having a housing composed of at least one shell and at least two parallel end parts and comprising an inlet passage provided with a throttle and an outlet passage. each shell being arranged between two end parts and being connected thereto to bound an interior space, a multi-apex piston rotatably arranged in the space and provided with sealing members sliding along the inner surfaces of the housing, an air passage communicating with the atmosphere at one end and opening into the intake chamber near the inlet passage at the other end, an air throttling means arranged within said air passage and coupled with the throttle. which means affords a small flow cross section when the throttle is closed, and a progressively enlarging flow cross-section as the throttle progressively opens, and lubricant supply means including a lubricant supply passage opening into said air passage for providing lubrication of said inner surfaces.

2. A rotary piston combustion engine according to claim 1 in which tension bolts assemble the shell and end parts and an enlarged hole receives each bolt. the passage in communication with the atmosphere leads from the axial midpoint of the shell outer surface in a radial direction and opens into an enlarged tension bolt hole nearest the inlet passage.'arid the adjacent faces of the end parts each provided with a groove extending from the bolt hole to a point in the intake chamber.

3. A rotary piston combustion engine according to claim 2 in which the cross-section of the groove in the end part has a profile guiding the flow obliquely radially outward towards the shell inner surface.

4. A rotary piston combustion engine according to claim 2 in which the groove opens into the intake chamber near the inlet port in the region where the tilting angle of the radial sealing strips is greatest.

5. A rotary piston combustion engine according to claim 1 in which the air throttling means includes a throttle and a rotary control valve determining the volume of air flow. arranged on the shaft of the throttle. the valve being enclosed by a housing provided with one air inlet and one air outlet coupled with the en larged bolt hole.

6. A rotary piston combustion engine according to claim 1 in which a spring loaded check valve opens under oil pressure arranged in the piping of the lubricant orifice.

7. A rotary piston combustion engine according to claim 1 in which means are provided for connecting the air passage to a source of fuel during cold starting of the engine. 

1. A Rotary piston combustion engine of trochoid type having a housing composed of at least one shell and at least two parallel end parts and comprising an inlet passage provided with a throttle and an outlet passage, each shell being arranged between two end parts and being connected thereto to bound an interior space, a multi-apex piston rotatably arranged in the space and provided with sealing members sliding along the inner surfaces of the housing, an air passage communicating with the atmosphere at one end and opening into the intake chamber near the inlet passage at the other end, an air throttling means arranged within said air passage and coupled with the throttle, which means affords a small flow cross section when the throttle is closed, and a progressively enlarging flow cross-section as the throttle progressively opens, and lubricant supply means including a lubricant supply passage opening into said air passage for providing lubrication of said inner surfaces.
 2. A rotary piston combustion engine according to claim 1 in which tension bolts assemble the shell and end parts and an enlarged hole receives each bolt, the passage in communication with the atmosphere leads from the axial midpoint of the shell outer surface in a radial direction and opens into an enlarged tension bolt hole nearest the inlet passage, and the adjacent faces of the end parts each provided with a groove extending from the bolt hole to a point in the intake chamber.
 3. A rotary piston combustion engine according to claim 2 in which the cross-section of the groove in the end part has a profile guiding the flow obliquely radially outward towards the shell inner surface.
 4. A rotary piston combustion engine according to claim 2 in which the groove opens into the intake chamber near the inlet port in the region where the tilting angle of the radial sealing strips is greatest.
 5. A rotary piston combustion engine according to claim 1 in which the air throttling means includes a throttle and a rotary control valve determining the volume of air flow, arranged on the shaft of the throttle, the valve being enclosed by a housing provided with one air inlet and one air outlet coupled with the enlarged bolt hole.
 6. A rotary piston combustion engine according to claim 1 in which a spring-loaded check valve opens under oil pressure arranged in the piping of the lubricant orifice.
 7. A rotary piston combustion engine according to claim 1 in which means are provided for connecting the air passage to a source of fuel during cold starting of the engine. 